Containers with several chambers of the nature mentioned above are well-established and are mainly used in biochemical and pharmaceutical applications if a plurality of probes has to be tested simultaneously. Special applications are, for example, electroporation, electrofusion and electrostimulation of living cells as well as all applications with which the probe has to be exposed to an electric field. The aim is to provide a large number of chambers, e.g. 96 or 384, especially with HT-analyses (HT=high throughput), as a maximum amount of samples is to be tested in a minimum time frame. Usually such containers are called multiwell plates, microtiter plates or multiwells.
Usually the known containers consist of several chambers that are provided with two electrodes, respectively, which are in contact with the probe, e.g. a cell suspension in the chamber. The two electrodes of a chamber generate an electric field within the chamber if an electric voltage is applied, whereby they show different polarities, for example, when direct current is used. The electrodes of same polarity of different chambers, i.e. all cathodes and/or all anodes, are all made of one piece or are coupled electrically so that they can be electrically connected via a common voltage source. Such arrangements have the advantage of a relatively simple assembly but, however, it is a disadvantage that the electrical parameter for all chambers is the same and consequently the individual operation of individual chambers is not possible.
Devices for the electrical stimulation of living cells are well-known, for example from US 2002/0028480 A1. In one embodiment, band-like electrodes are arranged in pairs on the ground of a multiwell plate. The band-like electrodes respectively protrude into the individual chambers of said plates and thus are in electric contact with the probes. Each band-like electrode has a contact area at one of its open ends, to which a voltage generator can be connected. One pair of electrodes is respectively assigned to one row of chambers. In a special embodiment some of the electrodes, e.g. all anodes, are short-circuited while the respective other part of electrodes of a row, e.g. the cathodes, are connected separately. In each case, however, with these well-known arrangements only entire rows of chambers can be activated, i.e. electrical parameter can only be adjusted for entire groups of chambers and not individually for each chamber.
From DE 199 17 571 A1 an electrode array for electroporation assays is known that consists of a planar arrangement of electric conducting paths on the surface of an electric insulator. The conducting paths are arranged in oppositely arranged ramifications and comprise single reaction areas for receiving probes for electroporation. The oppositely arranged conducting paths act as electrodes when an electric voltage is applied, whereby the respective conducting paths merge in a single main path that is connected to the voltage generator. As a consequence, even with this known arrangement no variable adjustment of electric parameter is possible so that all reaction areas are exposed to the same electric conditions.
WO 03/057819 A1 describes, among other things, also multiwell plates where the electrodes of different chambers are electrically connected at least in pairs so that the electrical parameter can be adjusted only for single groups of chambers and not for each chamber individually.
There is a need for a container as mentioned above that enables a flexible, individual and fast generation of electric fields in individual chambers of a container as well as a device for the safe and reliable electrical contacting of said container. Furthermore, there is a need for an inexpensive manufacturing method for such a container.